Connection terminal and plug.



No. 747,911'. l PATENTED DEG. 22, 190s. l

` W. W.DLA1-1. GONNBCTIONTERMINAL AND PLUG. APPLICATION FILED DEO.26,1900.' BENBWED HY. 23, 19.03.

N0 MODEL.

' UNITED STATES ratnte eeember 22, 1903.

PATENT OFFICE.'

WILLIAM W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO KELLOGG SWITCH- BOARDANDV SUPPLY COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

CONNECTION TERMINAL AND PLUG.

, SPECIFICATION forming part of Letters Patent No. 747,911, datedDecember 22, 1903. Application filed December 26, 1900. Renewed May 23,1903. Serial No. 168,646.Y (No model.)

To all whom, it may concern,.-

Be it known that I, WILLIAM'W. DEAN, a citizen of the United States,residing 'at Chicago, inthe county of Cook and State of Illinois, haveinvented a certain new and useful Improvement in. Connection Terminalsand Plugs, of which the following is a full, clear, concise, and exactdescription, reference being had to the accompanying drawings, formroing a part of this specification.

My invention relates to a connection terminal and plug more particularlydesigned for telephone-switchboards. My object is to provide improvedforms of Aterminal and plug which will enable the-construction of a-morecompact switchboard than has 'been possible heretofore, and, moreover,to provide structures such that the wear will take place ony the plugrather than on the parts of the terzo minal or socket.

In telephone-switchboards as commonly constructed heretofore theconnecting-plug has been provided with a sleeve adapted to engage athimble or shell provided in the connection terminal or socket and alsowith a tip or head, usually spherical in form, adapted to engage aline-spring, the end of the linespring being built so that the same maybe iiexed upon the insertion of the plug, the end 3o of the line-springcarrying a ridge or shoul-k'V der adapted to engage the rear of thetipor head to thereby firmly and securely hold the plugin position in thesocket. Since the plug is cylindrical in form, the plug will occupydifferent rotated positions upon successive insertions in the socket,and accordingly a different portion of the head or tip will at differenttimes engage the line-spring. The line-spring, however,lwill be engagedeach 4o time at the same locality, and thus while the tip has `aninfinite number'of Wearing-surfaces-to Wit, the entireperiphery of theti pthe line-springjwill Wear along a single line, and in time thiswearing will progress to such a degree as to necessitate the removal ofthe line-spring and the insertion of a newlinespring in position.

It is the object of the present invention to construct the contacts ofthe socket andthe 5o contacts of the plug so that the wear will takekpropose to do away with the usual laterally- 'within the reach of oneoperator. In, accordance With my invention I am enabled t0 place on thecontacts of the plug rather than on the contacts of the socket. Sincethere are usually ten times the number of switchsockets on a switchboardthat there are connecting-plugs, the total Wear will thus be greatlydiminished. Moreover, it is much easier to renew the plug-contacts thanit is to renew the contacts ofthe sockets, since 4the plugs are exposedand may be readily handledyfor the purpose of repair, While the 6osocket-contacts are placed in the interior of the board and are usuallydifficult of access.

A further object of my invention is to render the socket-contacts morecompact. The size `of the opening of the switch-socket is usuallydetermined by the 'space' necessary for the mounting of thesocket-contacts. The

, plug may'usually be made of any size to accommodate the constructionof the socket. I

7o moving contact-spring as heretofore employed inthe switch-socket andpropose to employa shell or thimble. Accordingly since there are nolaterally-moving parts in the socket the size of the socket may bematerially decreased. y

Heretofore it has been possible to mount the switch-sockets upon aswitchboard so that a maximum of six thousand sockets aremounttWenty-five thousand sockets Within the reach of a single operator.By my invention I amtherefore enabled to do away with a great manytrunk-lines heretofore em- V ployed in large exchanges, andthe speed ofmakingconnections may thus be materially increased, since'one operatormay make the connections direct which it has been heretofore necessaryto make through the agency 9o of trunk-lines, and consequently with theas' sistance of one or more operators. 'Intaccordance with myinventionfin the preferred form I provide the switch-socket with theusual thimble at the forward'end of 95 the socket adapted to makecontact with the sleeve of the plug, and I employ in addition a secondthimble or shell having a suitable shoulder with which a lresilientltipon the plug is adapted to engage. I preferably form :oo

the shoulder on the thimble so that the same will extend entirely aroundthe thimble and so that the same will be concentric therewith. With thisform of thimble I employ a plug having a resilient tip which iseccentrically mounted, so that when the plug is inserted in the socketthe resilient tip Will ride over the shoulder and will engage the same,whereby the plug will be firmly and securely held in position. I mayform the shoulder in the socket eccentric and mount the resilient tip onthe plug concentric; but this latter construction, while permitting theformation of a compact socket, transfers the Wearing-surface to thesocket-contact, and is thus not as advantageous as the rst constructionabove mentioned, in which the concentric shoulder in the socket presentsan infinite number of Wearing-surfaces, while the tip of the plugpresents a single Wearing-surface, thus transferring the wear to theplug.

I have illustrated my invention in the accompanying drawings, in which-Figure l is a view showing a number of switch-sockets. Fig. 2 is a Viewof a portion of the switchboard and a connecting-plug. Fig. Sis a viewshowing the switch-socket in section and the plug with the inclosinginsulating-sleeve in section. Fig. 4t is a view similar to Fig. 3,showing another View of the plug. Figs. 5 and 6 are detail views of thefastening device employed in the plug. Fig. 7 is a detached view of theplug-tip and associated parts. Fig. 8 is a sectional view showing theplug inserted in the switch-socket. Fig. 9 is a sectional view of amodified form of switch-socket and plug. Fig. l0is an end View of thesocket shown in Fig. 9.

Like letters refer to like parts in the several figures.

The switchboard is preferably built in sections, each section comprisinga pair of blocks et d of rubber or other similar insulating material,the blocks having bores at intervals to receive the contact-thimbles.Each bore in the block d is provided With a thimble Z9, having a smoothbore and having the ends spun outward, as illustrated, to form a flaringmouth to assist in guiding the plug into position, the flaring endsserving, moreover, to securely maintain the thimble in position. Withinthe openings in the block d are mounted the thimbles b, having the endssimilarly spun outward to secure the same in position. The thimble bcarries an inwardly-extending ridge or shoulder b2, the shoulder beingconcentric with the bore of the thimble.

The plug as preferably constructed comprises a metallic cylindricalportion c, the forward end of which is exposed to form thesleeve-contact c' of the plug. One terminal of the cord-connector isadapted to be connected with the part c at the rear end of the plug.Surrounding the part c is a shell c2, of rubber or similar insulatingmaterial, held in position by means of a threaded collar c3, en-

gagiug threads carried upon the periphery of the part c. Within the boreof the part c is an insulating tube or sleeve c4, and Within this sleeveis mounted a bar c5 of metal, carrying upon the end the rod c6, upon theend of which is mounted the tip c7 of the plug. The tip of the plug isprovided with a threaded hole with which the threaded end of the rod c6is adapted to engage. The rod cG is laterally bent to cause the tip c7to occupy an eccentric position relatively to the sleeve c of the plug.The part c5 is secured in position by means of a plate cs, resting uponan insulating-block o9, the screws c10 C10 being passed through theplate o8 and block o9 and engaging tapped holes provided in the part c5.The tip-strand c11 is connected with the plate c8 and is thus inelectrical connection with the tip of the plug.

When the connecting-plug is inserted in the switch-socket orconnection-terminal, the plug-sleeve c' engages the thimble ZJ of theswitch-socket, and the tip c7 of the plug rides over the shoulder b2 tothe position shown in Fig. 8. The tip thus makes electrical contact withthe thimble b', and the engagement of the tip with the shoulder b2serves to securely maintain the plug in position. As the plug uponsuccessive insertions in the socket will occupy different positions, thetip of the plug will successively engage the shoulder b2 at differentpositions, and therefore while the wear will come upon the tip at aparticular point the shoulder will present an infinite number of linesof contact, and the wear upon the shoulder will thus be comparativelyslight. Since the tip of the plug is detachable, a new tip may bereadily placed in position at any time, and, moreover, the tip may berotated from time to time relatively to the rod cG to thereby present anew contact-surface.

In Figs. 9 and lO I have illustrated a modification in which the thimbleb3, adapted to be engaged by the tip of the plug, is provided with aneccentric shoulder b4, said shoulder extending around onlya portion ofthe thimble. The tip 012 of the plug is held in a concentric position,and when the plug is inserted in the socket the resilient tip is movedlaterally as the same passes over the shoulder b4 and engages theshoulder, as shown in Fig. 9. This construction permits the formation ofa socket with as small dimensions as the one above described, whereinthe shoulder is concentric; but it has the objection of transferring thewearing-surfaces to the socket. For this reason I prefer in practice toemploy the concentric shoulder on the socket and the eccentric tip onthe plug.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is-

l. The combination with a plug having a resilient tip, of a socket toreceive the plug and having a shoulder adapted to be engaged by saidresilient tip, the engagement of said ICO tip and shoulder beingeccentric to the center line of the socket and plug, substantially asdescribed.

2. A connecting-plug having one terminal in the form of a sleeve and theother terminal in the form of a'resilient tip mounted eccentric to saidsleeve, substantially as described. y

3. A connecting-plughaving one terminal in the form of a cylindricalsleeve and the other terminal in the form of a resilient tip mountedeccentric to said sleeve,substantially as described. l

4. A connecting-plug having a portion adapted to enter a suitablevsocket and provided with a bore in the end thereof, of a resilient rodmounted within said bore and a tip mounted upon the end of said rod andnormally maintained in an eccentric position, substantially asdescribed.

5. A connecting-plug having a cylindrical portion adapted to enter asuitable socket and provided with a bore in the end thereof, ofaresilient rod mounted within said bore and a tip mounted upon theend ofsaid rod and normally maintained in an eccentric position, substantiallyas described.

6. The combination with a socket having a terminal in the form of athimble, of a plug adapted to be inserted in said socket and having aresilient tip eccentrically mounted to engage said thimble when theVplug is so inserted, substantially as described.

7. The combination with a socket having a terminal in the form of athimble provided with a suitable shoulder, of a plug having a resilienttip adapted to engage said shoulder, substantially as described.

8. The combination with a plug having a sleeve portion and a resilienttip, of asocket having a cylindrical bore to receive the sleeve portionof said plug, and having a thimble carrying a shoulder adapted to beengaged by said resilient tip, substantially as described.

l 9. The combination with a plug having a cylindrical portion and aresilient tip, of a socket having a cylindrical bore to receivethecylindrical portion of said plug, and having a thimble carrying ashoulder adapted to be engaged by said resilient tip, substantially asdescribed.

10. The combination with a plug having a sleeve portion and a resilienttip, of a socket having a bore to receive the said sleeve portion ofsaid plug, and having also a thimble provided with a shoulder adapted tobe engaged by said resilient tip, the engagement of said tip andshoulder being eccentric to the center line of the socket and plug,substantially as described.

11. The combinationwith a socket having a contact-terminal provided witha concentric shoulder, of a plug having a resilienteccentrically-mounted tip adapted to engage said shoulder, substantiallyas described.

12. The combination with a socket having a terminal in the form of athimble provided with a concentric shoulder, of a plug having aresilient and eccentrically mounted tip adapted to engage said shoulder,substantially as described. j

13. The combination with a socket, having two contactterrninals each inthe form of a thimble, one of said thimbles carrying a concentricshoulder, of a plug having a sleeve to engage one of said terminals andhaving a resilient and eccentrically mounted tip adapted to engage theshoulder on the other terminal, substantially as described.

14. The combination With a socket having a terminal in the form of athimble provided with an inwardly-extending shoulder or ridge, of a plughaving a resilient tip adapted to engage said shoulder or ridge,substantially as described.

15. The combination with a socket having a terminal in the form of athimble carrying an inwardly-extending concentric shoulder or ridge, ofa plug having a resilient and eccentrically-mounted tip adapted toengage said shoulder or ridge, substantially as described.

16. The combination with a connectionsocket having only two terminals,one of said terminals being in the form of a thimble and having a bore,and the'other terminal being rigid 'and having a shoulder, of aconnectingplug having two contacts only, said contacts being adapted toregister with the said terminals of the connection-socket, one of saidcontacts being in the form of a sleeve and adapted to engage saidthimble when the plug is inserted in the socket, and the other contactbeing in the form of a resilient rod having a ball or enlargement at itsfree end, said ball or enlargement being adapted to engage over saidrigid shoulder when the plug is inserted in the socket and thereby lockthe plug within the socket, substantially as described.

ln witness whereof I have hereunto subscribed my name in the presence oftwo Witnesses.

' WILLIAM W. DEAN.

Witnesses: Y

W.CLYDE JONES, MAE R. RocHFoRD.

IOO

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